//Blowfish encryption (ECB, CBC and CTR mode) as defined by Bruce Schneier here: http://www.schneier.com/paper-blowfish-fse.html
//Complies with test vectors found here: http://www.schneier.com/code/vectors.txt
//non-standard mode provided to be usable with the javascript crypto library found here: http://etherhack.co.uk/symmetric/blowfish/blowfish.html
//By FireXware, 1/7/1010, Contact: firexware@hotmail.com
//Code is partly adopted from the javascript crypto library by Daniel Rench

/*USAGE:

Provide the key when creating the object. The key can be any size up to 448 bits.
The key can be given as a hex string or an array of bytes.
  BlowFish b = new BlowFish("04B915BA43FEB5B6");

The plainText can be either a string or byte array.
  string plainText = "The quick brown fox jumped over the lazy dog.";

Use the Encypt_* methods to encrypt the plaintext in the mode that you want.
To Encrypt or decrypt a byte array using CBC or CTR mode, an array of bytes, you must provide an initialization vector.
A random IV can be created by calling SetRandomIV, then accessed with the IV property as it will be required to decrypt the data.
It is safe for the IV to be known by an attacker, as long as it is NEVER reused. IVs are handled automatically when encrypting and decrypting strings.
  string cipherText = b.Encrypt_CBC(plainText);
  MessageBox.Show(cipherText);

Use the same mode of operation for decryption.
  plainText = b.Decrypt_CBC(cipherText);
  MessageBox.Show(plainText);
*/

/*Which mode should I use?
 *---ECB---
 *  ECB mode encrypts each block of data with the same key, so patterns in a large set of data will be visible. 
 *  Encrypting the same data with the same key will result in the same ciphertext. This mode should NOT be used unless neccessary.
 *  
 *---CBC---
 *  CBC mode encrypts each block of data in succession so that any changes in the data will result in a completly different ciphertext.
 *  Also, an IV is used so that encrypting the same data with the same key will result in a different ciphertext. 
 *  CBC mode is the most popular mode of operation.
 *  
 *---CTR---
 *  CTR mode uses an IV and a counter to encrypt each block individually. 
 *  Like ECB mode, with the added protection of an IV to make sure the same plaintext encrypted with the same key yeilds a different result.
 *  The counter ensures that no patterns will be visible. CTR mode is secure and can be optimized for multi-threaded applications.
 * 
 * For more information on cipher modes of operation, see http://en.wikipedia.org/wiki/Block_cipher_modes_of_operation
 */

/*Things to remember
 * -Always use unique initialization vectors when using CBC and CTR mode. SetRandomIV will do the job for you.
 * -Blowfish is only as secure as the key you provide. When derriving a key from a password, use a secure hash function such as SHA-256 to create the key.
 * -Read "Which mode should I use?" and choose the best mode for your application
 * -Use a MAC to ensure that the ciphertext and IV have not been modified.
 * -Do not use the compatibility mode unless neccessary.
 */

using System;
using System.Text;
using System.Security.Cryptography;

namespace BlowFishCS
{
    class BlowFish
    {
        #region "Global variables and constants"

        const int ROUNDS = 16; //standard is 16, to increase the number of rounds, bf_P needs to be equal to the number of rouds. Use digits of PI.

        //Random number generator for creating IVs
        RNGCryptoServiceProvider randomSource;

        //SBLOCKS
        private uint[] bf_s0;
        private uint[] bf_s1;
        private uint[] bf_s2;
        private uint[] bf_s3;

        private uint[] bf_P;

        //KEY
        private byte[] key;

        //HALF-BLOCKS
        private uint xl_par;
        private uint xr_par;

        //Initialization Vector for CBC and CTR mode
        private byte[] InitVector;
        private bool IVSet;

        //For compatibility with the javascript crypto library:
        //  http://etherhack.co.uk/symmetric/blowfish/blowfish.html
        private bool nonStandardMethod;

        #endregion

        #region "Constructors"

        /// <summary>
        /// Constructor for hex key
        /// </summary>
        /// <param name="hexKey">Cipher key as a hex string</param>
        public BlowFish(string hexKey)
        {
            randomSource = new RNGCryptoServiceProvider();
            SetupKey(HexToByte(hexKey));
        }

        /// <summary>
        /// Constructor for byte key
        /// </summary>
        /// <param name="cipherKey">Cipher key as a byte array</param>
        public BlowFish(byte[] cipherKey)
        {
            randomSource = new RNGCryptoServiceProvider();
            SetupKey(cipherKey);
        }

        #endregion

        #region "Public methods"

        /// <summary>
        /// Encrypts a string in CBC mode
        /// </summary>
        /// <param name="pt">Plaintext data to encrypt</param>
        /// <returns>Ciphertext with IV appended to front</returns>
        public string Encrypt_CBC(string pt)
        {
            if (!IVSet)
                SetRandomIV();
            return ByteToHex(InitVector) + ByteToHex(Encrypt_CBC(Encoding.ASCII.GetBytes(pt)));
        }

        /// <summary>
        /// Decrypts a string in CBC mode
        /// </summary>
        /// <param name="ct">Ciphertext with IV appended to front</param>
        /// <returns>Plaintext</returns>
        public string Decrypt_CBC(string ct)
        {
            IV = HexToByte(ct.Substring(0, 16));
            return Encoding.ASCII.GetString(Decrypt_CBC(HexToByte(ct.Substring(16)))).Replace("\0", "");
        }

        /// <summary>
        /// Decrypts a byte array in CBC mode.
        /// IV must be created and saved manually.
        /// </summary>
        /// <param name="ct">Ciphertext data to decrypt</param>
        /// <returns>Plaintext</returns>
        public byte[] Decrypt_CBC(byte[] ct)
        {
            return Crypt_CBC(ct, true);
        }

        /// <summary>
        /// Encrypts a byte array in CBC mode.
        /// IV must be created and saved manually.
        /// </summary>
        /// <param name="pt">Plaintext data to encrypt</param>
        /// <returns>Ciphertext</returns>
        public byte[] Encrypt_CBC(byte[] pt)
        {
            return Crypt_CBC(pt, false);
        }

        /// <summary>
        /// Encrypt a string in ECB mode
        /// </summary>
        /// <param name="pt">Plaintext to encrypt as ascii string</param>
        /// <returns>hex value of encrypted data</returns>
        public string Encrypt_ECB(string pt)
        {
            return ByteToHex(Encrypt_ECB(Encoding.ASCII.GetBytes(pt)));
        }

        /// <summary>
        /// Decrypts a string (ECB)
        /// </summary>
        /// <param name="ct">hHex string of the ciphertext</param>
        /// <returns>Plaintext ascii string</returns>
        public string Decrypt_ECB(string ct)
        {
            return Encoding.ASCII.GetString(Decrypt_ECB(HexToByte(ct))).Replace("\0", "");
        }

        /// <summary>
        /// Encrypts a byte array in ECB mode
        /// </summary>
        /// <param name="pt">Plaintext data</param>
        /// <returns>Ciphertext bytes</returns>
        public byte[] Encrypt_ECB(byte[] pt)
        {
            return Crypt_ECB(pt, false);
        }

        /// <summary>
        /// Decrypts a byte array (ECB)
        /// </summary>
        /// <param name="ct">Ciphertext byte array</param>
        /// <returns>Plaintext</returns>
        public byte[] Decrypt_ECB(byte[] ct)
        {
            return Crypt_ECB(ct, true);
        }

        /// <summary>
        /// Encrypts a string (CTR)
        /// </summary>
        /// <param name="pt">The plaintext to encrypt</param>
        /// <returns>The ciphertext</returns>
        public string Encrypt_CTR(string pt)
        {
            if (!IVSet)
                SetRandomIV();
            return ByteToHex(InitVector) + ByteToHex(Crypt_CTR(Encoding.ASCII.GetBytes(pt), 2));
        }

        /// <summary>
        /// Decrypt a string (CTR)
        /// </summary>
        /// <param name="ct">The ciphertext to decrypt</param>
        /// <returns>The plaintext</returns>
        public string Decrypt_CTR(string ct)
        {
            IV = HexToByte(ct.Substring(0, 16));
            return Encoding.ASCII.GetString(Crypt_CTR(HexToByte(ct.Substring(16)), 2)).Replace("\0", "");
        }

        /// <summary>
        /// Initialization vector for CBC mode.
        /// </summary>
        public byte[] IV
        {
            get { return InitVector; }
            set
            {
                if (value.Length == 8)
                {
                    InitVector = value;
                    IVSet = true;
                }
                else
                {
                    throw new Exception("Invalid IV size.");
                }
            }
        }

        public bool NonStandard
        {
            get { return nonStandardMethod; }
            set { nonStandardMethod = value; }
        }

        /// <summary>
        /// Creates and sets a random initialization vector.
        /// </summary>
        /// <returns>The random IV</returns>
        public byte[] SetRandomIV()
        {
            InitVector = new byte[8];
            randomSource.GetBytes(InitVector);
            IVSet = true;
            return InitVector;
        }

        #endregion

        #region Cryptography

        /// <summary>
        /// Sets up the S-blocks and the key
        /// </summary>
        /// <param name="cipherKey">Block cipher key (1-448 bits)</param>
        private void SetupKey(byte[] cipherKey)
        {
            bf_P = SetupP();
            //set up the S blocks
            bf_s0 = SetupS0();
            bf_s1 = SetupS1();
            bf_s2 = SetupS2();
            bf_s3 = SetupS3();

            key = new byte[cipherKey.Length]; // 448 bits
            if (cipherKey.Length > 56)
            {
                throw new Exception("Key too long. 56 bytes required.");
            }

            Buffer.BlockCopy(cipherKey, 0, key, 0, cipherKey.Length);
            int j = 0;
            for (int i = 0; i < 18; i++)
            {
                uint d = (uint)(((key[j % cipherKey.Length] * 256 + key[(j + 1) % cipherKey.Length]) * 256 + key[(j + 2) % cipherKey.Length]) * 256 + key[(j + 3) % cipherKey.Length]);
                bf_P[i] ^= d;
                j = (j + 4) % cipherKey.Length;
            }

            xl_par = 0;
            xr_par = 0;
            for (int i = 0; i < 18; i += 2)
            {
                encipher();
                bf_P[i] = xl_par;
                bf_P[i + 1] = xr_par;
            }

            for (int i = 0; i < 256; i += 2)
            {
                encipher();
                bf_s0[i] = xl_par;
                bf_s0[i + 1] = xr_par;
            }
            for (int i = 0; i < 256; i += 2)
            {
                encipher();
                bf_s1[i] = xl_par;
                bf_s1[i + 1] = xr_par;
            }
            for (int i = 0; i < 256; i += 2)
            {
                encipher();
                bf_s2[i] = xl_par;
                bf_s2[i + 1] = xr_par;
            }
            for (int i = 0; i < 256; i += 2)
            {
                encipher();
                bf_s3[i] = xl_par;
                bf_s3[i + 1] = xr_par;
            }
        }

        /// <summary>
        /// Encrypts or decrypts data in ECB mode
        /// </summary>
        /// <param name="text">plain/ciphertext</param>
        /// <param name="decrypt">true to decrypt, false to encrypt</param>
        /// <returns>(En/De)crypted data</returns>
        private byte[] Crypt_ECB(byte[] text, bool decrypt)
        {
            int paddedLen = (text.Length % 8 == 0 ? text.Length : text.Length + 8 - (text.Length % 8));
            byte[] plainText = new byte[paddedLen];
            Buffer.BlockCopy(text, 0, plainText, 0, text.Length);
            byte[] block = new byte[8];
            for (int i = 0; i < plainText.Length; i += 8)
            {
                Buffer.BlockCopy(plainText, i, block, 0, 8);
                if (decrypt)
                {
                    BlockDecrypt(ref block);
                }
                else
                {
                    BlockEncrypt(ref block);
                }
                Buffer.BlockCopy(block, 0, plainText, i, 8);
            }
            return plainText;
        }

        public byte[] Crypt_CTR(byte[] text, int numThreads)
        {
            if (!IVSet)
            {
                throw new Exception("IV not set.");
            }
            byte[] input = new byte[8];
            byte[] counter = new byte[8];
            int paddedLen = (text.Length % 8 == 0 ? text.Length : text.Length + 8 - (text.Length % 8));
            byte[] plainText = new byte[paddedLen];
            Buffer.BlockCopy(text, 0, plainText, 0, text.Length);
            byte[] block = new byte[8];
            for (int i = 0; i < plainText.Length; i += 8)
            {
                for (int x = 0; x < 8; x++)
                {
                    input[x] = (byte)(counter[x] ^ InitVector[x]);
                }
                Buffer.BlockCopy(plainText, i, block, 0, 8);
                BlockEncrypt(ref input);
                XorBlock(ref block, input);
                Buffer.BlockCopy(block, 0, plainText, i, 8);
            }
            return plainText;
        }

        /// <summary>
        /// Encrypts or decrypts data in CBC mode
        /// </summary>
        /// <param name="text">plain/ciphertext</param>
        /// <param name="decrypt">true to decrypt, false to encrypt</param>
        /// <returns>(En/De)crypted data</returns>
        private byte[] Crypt_CBC(byte[] text, bool decrypt)
        {
            if (!IVSet)
            {
                throw new Exception("IV not set.");
            }
            int paddedLen = (text.Length % 8 == 0 ? text.Length : text.Length + 8 - (text.Length % 8));
            byte[] plainText = new byte[paddedLen];
            Buffer.BlockCopy(text, 0, plainText, 0, text.Length);
            byte[] block = new byte[8];
            byte[] preblock = new byte[8];
            byte[] iv = new byte[8];
            Buffer.BlockCopy(InitVector, 0, iv, 0, 8);
            if (!decrypt)
            {
                for (int i = 0; i < plainText.Length; i += 8)
                {
                    Buffer.BlockCopy(plainText, i, block, 0, 8);
                    XorBlock(ref block, iv);
                    BlockEncrypt(ref block);
                    Buffer.BlockCopy(block, 0, iv, 0, 8);
                    Buffer.BlockCopy(block, 0, plainText, i, 8);
                }
            }
            else
            {
                for (int i = 0; i < plainText.Length; i += 8)
                {
                    Buffer.BlockCopy(plainText, i, block, 0, 8);

                    Buffer.BlockCopy(block, 0, preblock, 0, 8);
                    BlockDecrypt(ref block);
                    XorBlock(ref block, iv);
                    Buffer.BlockCopy(preblock, 0, iv, 0, 8);

                    Buffer.BlockCopy(block, 0, plainText, i, 8);
                }
            }
            return plainText;
        }

        /// <summary>
        /// XoR encrypts two 8 bit blocks
        /// </summary>
        /// <param name="block">8 bit block 1</param>
        /// <param name="iv">8 bit block 2</param>
        private void XorBlock(ref byte[] block, byte[] iv)
        {
            for (int i = 0; i < block.Length; i++)
            {
                block[i] ^= iv[i];
            }
        }

        /// <summary>
        /// Encrypts a 64 bit block
        /// </summary>
        /// <param name="block">The 64 bit block to encrypt</param>
        private void BlockEncrypt(ref byte[] block)
        {
            SetBlock(block);
            encipher();
            GetBlock(ref block);
        }

        /// <summary>
        /// Decrypts a 64 bit block
        /// </summary>
        /// <param name="block">The 64 bit block to decrypt</param>
        private void BlockDecrypt(ref byte[] block)
        {
            SetBlock(block);
            decipher();
            GetBlock(ref block);
        }

        /// <summary>
        /// Splits the block into the two uint values
        /// </summary>
        /// <param name="block">the 64 bit block to setup</param>
        private void SetBlock(byte[] block)
        {
            byte[] block1 = new byte[4];
            byte[] block2 = new byte[4];
            Buffer.BlockCopy(block, 0, block1, 0, 4);
            Buffer.BlockCopy(block, 4, block2, 0, 4);
            //split the block
            if (nonStandardMethod)
            {
                xr_par = BitConverter.ToUInt32(block1, 0);
                xl_par = BitConverter.ToUInt32(block2, 0);
            }
            else
            {
                //ToUInt32 requires the bytes in reverse order
                Array.Reverse(block1);
                Array.Reverse(block2);
                xl_par = BitConverter.ToUInt32(block1, 0);
                xr_par = BitConverter.ToUInt32(block2, 0);
            }
        }

        /// <summary>
        /// Converts the two uint values into a 64 bit block
        /// </summary>
        /// <param name="block">64 bit buffer to receive the block</param>
        private void GetBlock(ref byte[] block)
        {
            byte[] block1 = new byte[4];
            byte[] block2 = new byte[4];
            if (nonStandardMethod)
            {
                block1 = BitConverter.GetBytes(xr_par);
                block2 = BitConverter.GetBytes(xl_par);
            }
            else
            {
                block1 = BitConverter.GetBytes(xl_par);
                block2 = BitConverter.GetBytes(xr_par);

                //GetBytes returns the bytes in reverse order
                Array.Reverse(block1);
                Array.Reverse(block2);
            }
            //join the block
            Buffer.BlockCopy(block1, 0, block, 0, 4);
            Buffer.BlockCopy(block2, 0, block, 4, 4);
        }

        /// <summary>
        /// Runs the blowfish algorithm (standard 16 rounds)
        /// </summary>
        private void encipher()
        {
            xl_par ^= bf_P[0];
            for (uint i = 0; i < ROUNDS; i += 2)
            {
                xr_par = round(xr_par, xl_par, i + 1);
                xl_par = round(xl_par, xr_par, i + 2);
            }
            xr_par = xr_par ^ bf_P[17];

            //swap the blocks
            uint swap = xl_par;
            xl_par = xr_par;
            xr_par = swap;
        }

        /// <summary>
        /// Runs the blowfish algorithm in reverse (standard 16 rounds)
        /// </summary>
        private void decipher()
        {
            xl_par ^= bf_P[17];
            for (uint i = 16; i > 0; i -= 2)
            {
                xr_par = round(xr_par, xl_par, i);
                xl_par = round(xl_par, xr_par, i - 1);
            }
            xr_par = xr_par ^ bf_P[0];

            //swap the blocks
            uint swap = xl_par;
            xl_par = xr_par;
            xr_par = swap;
        }

        /// <summary>
        /// one round of the blowfish algorithm
        /// </summary>
        /// <param name="a">See spec</param>
        /// <param name="b">See spec</param>
        /// <param name="n">See spec</param>
        /// <returns></returns>
        private uint round(uint a, uint b, uint n)
        {
            uint x1 = (bf_s0[wordByte0(b)] + bf_s1[wordByte1(b)]) ^ bf_s2[wordByte2(b)];
            uint x2 = x1 + bf_s3[this.wordByte3(b)];
            uint x3 = x2 ^ bf_P[n];
            return x3 ^ a;
        }

        #endregion

        #region SBLOCKS
        //SBLOCKS ARE THE HEX DIGITS OF PI. 
        //The amount of hex digits can be increased if you want to experiment with more rounds and longer key lengths

        //Increase the size of this array when increasing the number of rounds
        private uint[] SetupP()
        {
            return new uint[] {
                0x243f6a88,0x85a308d3,0x13198a2e,0x03707344,0xa4093822,0x299f31d0,
                    0x082efa98,0xec4e6c89,0x452821e6,0x38d01377,0xbe5466cf,0x34e90c6c,
                    0xc0ac29b7,0xc97c50dd,0x3f84d5b5,0xb5470917,0x9216d5d9,0x8979fb1b
            };
        }

        private uint[] SetupS0()
        {
            return new uint[] {
                    0xd1310ba6,0x98dfb5ac,0x2ffd72db,0xd01adfb7,0xb8e1afed,0x6a267e96,
                    0xba7c9045,0xf12c7f99,0x24a19947,0xb3916cf7,0x0801f2e2,0x858efc16,
                    0x636920d8,0x71574e69,0xa458fea3,0xf4933d7e,0x0d95748f,0x728eb658,
                    0x718bcd58,0x82154aee,0x7b54a41d,0xc25a59b5,0x9c30d539,0x2af26013,
                    0xc5d1b023,0x286085f0,0xca417918,0xb8db38ef,0x8e79dcb0,0x603a180e,
                    0x6c9e0e8b,0xb01e8a3e,0xd71577c1,0xbd314b27,0x78af2fda,0x55605c60,
                    0xe65525f3,0xaa55ab94,0x57489862,0x63e81440,0x55ca396a,0x2aab10b6,
                    0xb4cc5c34,0x1141e8ce,0xa15486af,0x7c72e993,0xb3ee1411,0x636fbc2a,
                    0x2ba9c55d,0x741831f6,0xce5c3e16,0x9b87931e,0xafd6ba33,0x6c24cf5c,
                    0x7a325381,0x28958677,0x3b8f4898,0x6b4bb9af,0xc4bfe81b,0x66282193,
                    0x61d809cc,0xfb21a991,0x487cac60,0x5dec8032,0xef845d5d,0xe98575b1,
                    0xdc262302,0xeb651b88,0x23893e81,0xd396acc5,0x0f6d6ff3,0x83f44239,
                    0x2e0b4482,0xa4842004,0x69c8f04a,0x9e1f9b5e,0x21c66842,0xf6e96c9a,
                    0x670c9c61,0xabd388f0,0x6a51a0d2,0xd8542f68,0x960fa728,0xab5133a3,
                    0x6eef0b6c,0x137a3be4,0xba3bf050,0x7efb2a98,0xa1f1651d,0x39af0176,
                    0x66ca593e,0x82430e88,0x8cee8619,0x456f9fb4,0x7d84a5c3,0x3b8b5ebe,
                    0xe06f75d8,0x85c12073,0x401a449f,0x56c16aa6,0x4ed3aa62,0x363f7706,
                    0x1bfedf72,0x429b023d,0x37d0d724,0xd00a1248,0xdb0fead3,0x49f1c09b,
                    0x075372c9,0x80991b7b,0x25d479d8,0xf6e8def7,0xe3fe501a,0xb6794c3b,
                    0x976ce0bd,0x04c006ba,0xc1a94fb6,0x409f60c4,0x5e5c9ec2,0x196a2463,
                    0x68fb6faf,0x3e6c53b5,0x1339b2eb,0x3b52ec6f,0x6dfc511f,0x9b30952c,
                    0xcc814544,0xaf5ebd09,0xbee3d004,0xde334afd,0x660f2807,0x192e4bb3,
                    0xc0cba857,0x45c8740f,0xd20b5f39,0xb9d3fbdb,0x5579c0bd,0x1a60320a,
                    0xd6a100c6,0x402c7279,0x679f25fe,0xfb1fa3cc,0x8ea5e9f8,0xdb3222f8,
                    0x3c7516df,0xfd616b15,0x2f501ec8,0xad0552ab,0x323db5fa,0xfd238760,
                    0x53317b48,0x3e00df82,0x9e5c57bb,0xca6f8ca0,0x1a87562e,0xdf1769db,
                    0xd542a8f6,0x287effc3,0xac6732c6,0x8c4f5573,0x695b27b0,0xbbca58c8,
                    0xe1ffa35d,0xb8f011a0,0x10fa3d98,0xfd2183b8,0x4afcb56c,0x2dd1d35b,
                    0x9a53e479,0xb6f84565,0xd28e49bc,0x4bfb9790,0xe1ddf2da,0xa4cb7e33,
                    0x62fb1341,0xcee4c6e8,0xef20cada,0x36774c01,0xd07e9efe,0x2bf11fb4,
                    0x95dbda4d,0xae909198,0xeaad8e71,0x6b93d5a0,0xd08ed1d0,0xafc725e0,
                    0x8e3c5b2f,0x8e7594b7,0x8ff6e2fb,0xf2122b64,0x8888b812,0x900df01c,
                    0x4fad5ea0,0x688fc31c,0xd1cff191,0xb3a8c1ad,0x2f2f2218,0xbe0e1777,
                    0xea752dfe,0x8b021fa1,0xe5a0cc0f,0xb56f74e8,0x18acf3d6,0xce89e299,
                    0xb4a84fe0,0xfd13e0b7,0x7cc43b81,0xd2ada8d9,0x165fa266,0x80957705,
                    0x93cc7314,0x211a1477,0xe6ad2065,0x77b5fa86,0xc75442f5,0xfb9d35cf,
                    0xebcdaf0c,0x7b3e89a0,0xd6411bd3,0xae1e7e49,0x00250e2d,0x2071b35e,
                    0x226800bb,0x57b8e0af,0x2464369b,0xf009b91e,0x5563911d,0x59dfa6aa,
                    0x78c14389,0xd95a537f,0x207d5ba2,0x02e5b9c5,0x83260376,0x6295cfa9,
                    0x11c81968,0x4e734a41,0xb3472dca,0x7b14a94a,0x1b510052,0x9a532915,
                    0xd60f573f,0xbc9bc6e4,0x2b60a476,0x81e67400,0x08ba6fb5,0x571be91f,
                    0xf296ec6b,0x2a0dd915,0xb6636521,0xe7b9f9b6,0xff34052e,0xc5855664,
                    0x53b02d5d,0xa99f8fa1,0x08ba4799,0x6e85076a
            };
        }

        private uint[] SetupS1()
        {
            return new uint[] {
                0x4b7a70e9,0xb5b32944,0xdb75092e,0xc4192623,0xad6ea6b0,0x49a7df7d,
                    0x9cee60b8,0x8fedb266,0xecaa8c71,0x699a17ff,0x5664526c,0xc2b19ee1,
                    0x193602a5,0x75094c29,0xa0591340,0xe4183a3e,0x3f54989a,0x5b429d65,
                    0x6b8fe4d6,0x99f73fd6,0xa1d29c07,0xefe830f5,0x4d2d38e6,0xf0255dc1,
                    0x4cdd2086,0x8470eb26,0x6382e9c6,0x021ecc5e,0x09686b3f,0x3ebaefc9,
                    0x3c971814,0x6b6a70a1,0x687f3584,0x52a0e286,0xb79c5305,0xaa500737,
                    0x3e07841c,0x7fdeae5c,0x8e7d44ec,0x5716f2b8,0xb03ada37,0xf0500c0d,
                    0xf01c1f04,0x0200b3ff,0xae0cf51a,0x3cb574b2,0x25837a58,0xdc0921bd,
                    0xd19113f9,0x7ca92ff6,0x94324773,0x22f54701,0x3ae5e581,0x37c2dadc,
                    0xc8b57634,0x9af3dda7,0xa9446146,0x0fd0030e,0xecc8c73e,0xa4751e41,
                    0xe238cd99,0x3bea0e2f,0x3280bba1,0x183eb331,0x4e548b38,0x4f6db908,
                    0x6f420d03,0xf60a04bf,0x2cb81290,0x24977c79,0x5679b072,0xbcaf89af,
                    0xde9a771f,0xd9930810,0xb38bae12,0xdccf3f2e,0x5512721f,0x2e6b7124,
                    0x501adde6,0x9f84cd87,0x7a584718,0x7408da17,0xbc9f9abc,0xe94b7d8c,
                    0xec7aec3a,0xdb851dfa,0x63094366,0xc464c3d2,0xef1c1847,0x3215d908,
                    0xdd433b37,0x24c2ba16,0x12a14d43,0x2a65c451,0x50940002,0x133ae4dd,
                    0x71dff89e,0x10314e55,0x81ac77d6,0x5f11199b,0x043556f1,0xd7a3c76b,
                    0x3c11183b,0x5924a509,0xf28fe6ed,0x97f1fbfa,0x9ebabf2c,0x1e153c6e,
                    0x86e34570,0xeae96fb1,0x860e5e0a,0x5a3e2ab3,0x771fe71c,0x4e3d06fa,
                    0x2965dcb9,0x99e71d0f,0x803e89d6,0x5266c825,0x2e4cc978,0x9c10b36a,
                    0xc6150eba,0x94e2ea78,0xa5fc3c53,0x1e0a2df4,0xf2f74ea7,0x361d2b3d,
                    0x1939260f,0x19c27960,0x5223a708,0xf71312b6,0xebadfe6e,0xeac31f66,
                    0xe3bc4595,0xa67bc883,0xb17f37d1,0x018cff28,0xc332ddef,0xbe6c5aa5,
                    0x65582185,0x68ab9802,0xeecea50f,0xdb2f953b,0x2aef7dad,0x5b6e2f84,
                    0x1521b628,0x29076170,0xecdd4775,0x619f1510,0x13cca830,0xeb61bd96,
                    0x0334fe1e,0xaa0363cf,0xb5735c90,0x4c70a239,0xd59e9e0b,0xcbaade14,
                    0xeecc86bc,0x60622ca7,0x9cab5cab,0xb2f3846e,0x648b1eaf,0x19bdf0ca,
                    0xa02369b9,0x655abb50,0x40685a32,0x3c2ab4b3,0x319ee9d5,0xc021b8f7,
                    0x9b540b19,0x875fa099,0x95f7997e,0x623d7da8,0xf837889a,0x97e32d77,
                    0x11ed935f,0x16681281,0x0e358829,0xc7e61fd6,0x96dedfa1,0x7858ba99,
                    0x57f584a5,0x1b227263,0x9b83c3ff,0x1ac24696,0xcdb30aeb,0x532e3054,
                    0x8fd948e4,0x6dbc3128,0x58ebf2ef,0x34c6ffea,0xfe28ed61,0xee7c3c73,
                    0x5d4a14d9,0xe864b7e3,0x42105d14,0x203e13e0,0x45eee2b6,0xa3aaabea,
                    0xdb6c4f15,0xfacb4fd0,0xc742f442,0xef6abbb5,0x654f3b1d,0x41cd2105,
                    0xd81e799e,0x86854dc7,0xe44b476a,0x3d816250,0xcf62a1f2,0x5b8d2646,
                    0xfc8883a0,0xc1c7b6a3,0x7f1524c3,0x69cb7492,0x47848a0b,0x5692b285,
                    0x095bbf00,0xad19489d,0x1462b174,0x23820e00,0x58428d2a,0x0c55f5ea,
                    0x1dadf43e,0x233f7061,0x3372f092,0x8d937e41,0xd65fecf1,0x6c223bdb,
                    0x7cde3759,0xcbee7460,0x4085f2a7,0xce77326e,0xa6078084,0x19f8509e,
                    0xe8efd855,0x61d99735,0xa969a7aa,0xc50c06c2,0x5a04abfc,0x800bcadc,
                    0x9e447a2e,0xc3453484,0xfdd56705,0x0e1e9ec9,0xdb73dbd3,0x105588cd,
                    0x675fda79,0xe3674340,0xc5c43465,0x713e38d8,0x3d28f89e,0xf16dff20,
                    0x153e21e7,0x8fb03d4a,0xe6e39f2b,0xdb83adf7
            };
        }

        private uint[] SetupS2()
        {
            return new uint[] {
                0xe93d5a68,0x948140f7,0xf64c261c,0x94692934,0x411520f7,0x7602d4f7,
                    0xbcf46b2e,0xd4a20068,0xd4082471,0x3320f46a,0x43b7d4b7,0x500061af,
                    0x1e39f62e,0x97244546,0x14214f74,0xbf8b8840,0x4d95fc1d,0x96b591af,
                    0x70f4ddd3,0x66a02f45,0xbfbc09ec,0x03bd9785,0x7fac6dd0,0x31cb8504,
                    0x96eb27b3,0x55fd3941,0xda2547e6,0xabca0a9a,0x28507825,0x530429f4,
                    0x0a2c86da,0xe9b66dfb,0x68dc1462,0xd7486900,0x680ec0a4,0x27a18dee,
                    0x4f3ffea2,0xe887ad8c,0xb58ce006,0x7af4d6b6,0xaace1e7c,0xd3375fec,
                    0xce78a399,0x406b2a42,0x20fe9e35,0xd9f385b9,0xee39d7ab,0x3b124e8b,
                    0x1dc9faf7,0x4b6d1856,0x26a36631,0xeae397b2,0x3a6efa74,0xdd5b4332,
                    0x6841e7f7,0xca7820fb,0xfb0af54e,0xd8feb397,0x454056ac,0xba489527,
                    0x55533a3a,0x20838d87,0xfe6ba9b7,0xd096954b,0x55a867bc,0xa1159a58,
                    0xcca92963,0x99e1db33,0xa62a4a56,0x3f3125f9,0x5ef47e1c,0x9029317c,
                    0xfdf8e802,0x04272f70,0x80bb155c,0x05282ce3,0x95c11548,0xe4c66d22,
                    0x48c1133f,0xc70f86dc,0x07f9c9ee,0x41041f0f,0x404779a4,0x5d886e17,
                    0x325f51eb,0xd59bc0d1,0xf2bcc18f,0x41113564,0x257b7834,0x602a9c60,
                    0xdff8e8a3,0x1f636c1b,0x0e12b4c2,0x02e1329e,0xaf664fd1,0xcad18115,
                    0x6b2395e0,0x333e92e1,0x3b240b62,0xeebeb922,0x85b2a20e,0xe6ba0d99,
                    0xde720c8c,0x2da2f728,0xd0127845,0x95b794fd,0x647d0862,0xe7ccf5f0,
                    0x5449a36f,0x877d48fa,0xc39dfd27,0xf33e8d1e,0x0a476341,0x992eff74,
                    0x3a6f6eab,0xf4f8fd37,0xa812dc60,0xa1ebddf8,0x991be14c,0xdb6e6b0d,
                    0xc67b5510,0x6d672c37,0x2765d43b,0xdcd0e804,0xf1290dc7,0xcc00ffa3,
                    0xb5390f92,0x690fed0b,0x667b9ffb,0xcedb7d9c,0xa091cf0b,0xd9155ea3,
                    0xbb132f88,0x515bad24,0x7b9479bf,0x763bd6eb,0x37392eb3,0xcc115979,
                    0x8026e297,0xf42e312d,0x6842ada7,0xc66a2b3b,0x12754ccc,0x782ef11c,
                    0x6a124237,0xb79251e7,0x06a1bbe6,0x4bfb6350,0x1a6b1018,0x11caedfa,
                    0x3d25bdd8,0xe2e1c3c9,0x44421659,0x0a121386,0xd90cec6e,0xd5abea2a,
                    0x64af674e,0xda86a85f,0xbebfe988,0x64e4c3fe,0x9dbc8057,0xf0f7c086,
                    0x60787bf8,0x6003604d,0xd1fd8346,0xf6381fb0,0x7745ae04,0xd736fccc,
                    0x83426b33,0xf01eab71,0xb0804187,0x3c005e5f,0x77a057be,0xbde8ae24,
                    0x55464299,0xbf582e61,0x4e58f48f,0xf2ddfda2,0xf474ef38,0x8789bdc2,
                    0x5366f9c3,0xc8b38e74,0xb475f255,0x46fcd9b9,0x7aeb2661,0x8b1ddf84,
                    0x846a0e79,0x915f95e2,0x466e598e,0x20b45770,0x8cd55591,0xc902de4c,
                    0xb90bace1,0xbb8205d0,0x11a86248,0x7574a99e,0xb77f19b6,0xe0a9dc09,
                    0x662d09a1,0xc4324633,0xe85a1f02,0x09f0be8c,0x4a99a025,0x1d6efe10,
                    0x1ab93d1d,0x0ba5a4df,0xa186f20f,0x2868f169,0xdcb7da83,0x573906fe,
                    0xa1e2ce9b,0x4fcd7f52,0x50115e01,0xa70683fa,0xa002b5c4,0x0de6d027,
                    0x9af88c27,0x773f8641,0xc3604c06,0x61a806b5,0xf0177a28,0xc0f586e0,
                    0x006058aa,0x30dc7d62,0x11e69ed7,0x2338ea63,0x53c2dd94,0xc2c21634,
                    0xbbcbee56,0x90bcb6de,0xebfc7da1,0xce591d76,0x6f05e409,0x4b7c0188,
                    0x39720a3d,0x7c927c24,0x86e3725f,0x724d9db9,0x1ac15bb4,0xd39eb8fc,
                    0xed545578,0x08fca5b5,0xd83d7cd3,0x4dad0fc4,0x1e50ef5e,0xb161e6f8,
                    0xa28514d9,0x6c51133c,0x6fd5c7e7,0x56e14ec4,0x362abfce,0xddc6c837,
                    0xd79a3234,0x92638212,0x670efa8e,0x406000e0
            };
        }

        private uint[] SetupS3()
        {
            return new uint[] {
                    0x3a39ce37,0xd3faf5cf,0xabc27737,0x5ac52d1b,0x5cb0679e,0x4fa33742,
                    0xd3822740,0x99bc9bbe,0xd5118e9d,0xbf0f7315,0xd62d1c7e,0xc700c47b,
                    0xb78c1b6b,0x21a19045,0xb26eb1be,0x6a366eb4,0x5748ab2f,0xbc946e79,
                    0xc6a376d2,0x6549c2c8,0x530ff8ee,0x468dde7d,0xd5730a1d,0x4cd04dc6,
                    0x2939bbdb,0xa9ba4650,0xac9526e8,0xbe5ee304,0xa1fad5f0,0x6a2d519a,
                    0x63ef8ce2,0x9a86ee22,0xc089c2b8,0x43242ef6,0xa51e03aa,0x9cf2d0a4,
                    0x83c061ba,0x9be96a4d,0x8fe51550,0xba645bd6,0x2826a2f9,0xa73a3ae1,
                    0x4ba99586,0xef5562e9,0xc72fefd3,0xf752f7da,0x3f046f69,0x77fa0a59,
                    0x80e4a915,0x87b08601,0x9b09e6ad,0x3b3ee593,0xe990fd5a,0x9e34d797,
                    0x2cf0b7d9,0x022b8b51,0x96d5ac3a,0x017da67d,0xd1cf3ed6,0x7c7d2d28,
                    0x1f9f25cf,0xadf2b89b,0x5ad6b472,0x5a88f54c,0xe029ac71,0xe019a5e6,
                    0x47b0acfd,0xed93fa9b,0xe8d3c48d,0x283b57cc,0xf8d56629,0x79132e28,
                    0x785f0191,0xed756055,0xf7960e44,0xe3d35e8c,0x15056dd4,0x88f46dba,
                    0x03a16125,0x0564f0bd,0xc3eb9e15,0x3c9057a2,0x97271aec,0xa93a072a,
                    0x1b3f6d9b,0x1e6321f5,0xf59c66fb,0x26dcf319,0x7533d928,0xb155fdf5,
                    0x03563482,0x8aba3cbb,0x28517711,0xc20ad9f8,0xabcc5167,0xccad925f,
                    0x4de81751,0x3830dc8e,0x379d5862,0x9320f991,0xea7a90c2,0xfb3e7bce,
                    0x5121ce64,0x774fbe32,0xa8b6e37e,0xc3293d46,0x48de5369,0x6413e680,
                    0xa2ae0810,0xdd6db224,0x69852dfd,0x09072166,0xb39a460a,0x6445c0dd,
                    0x586cdecf,0x1c20c8ae,0x5bbef7dd,0x1b588d40,0xccd2017f,0x6bb4e3bb,
                    0xdda26a7e,0x3a59ff45,0x3e350a44,0xbcb4cdd5,0x72eacea8,0xfa6484bb,
                    0x8d6612ae,0xbf3c6f47,0xd29be463,0x542f5d9e,0xaec2771b,0xf64e6370,
                    0x740e0d8d,0xe75b1357,0xf8721671,0xaf537d5d,0x4040cb08,0x4eb4e2cc,
                    0x34d2466a,0x0115af84,0xe1b00428,0x95983a1d,0x06b89fb4,0xce6ea048,
                    0x6f3f3b82,0x3520ab82,0x011a1d4b,0x277227f8,0x611560b1,0xe7933fdc,
                    0xbb3a792b,0x344525bd,0xa08839e1,0x51ce794b,0x2f32c9b7,0xa01fbac9,
                    0xe01cc87e,0xbcc7d1f6,0xcf0111c3,0xa1e8aac7,0x1a908749,0xd44fbd9a,
                    0xd0dadecb,0xd50ada38,0x0339c32a,0xc6913667,0x8df9317c,0xe0b12b4f,
                    0xf79e59b7,0x43f5bb3a,0xf2d519ff,0x27d9459c,0xbf97222c,0x15e6fc2a,
                    0x0f91fc71,0x9b941525,0xfae59361,0xceb69ceb,0xc2a86459,0x12baa8d1,
                    0xb6c1075e,0xe3056a0c,0x10d25065,0xcb03a442,0xe0ec6e0e,0x1698db3b,
                    0x4c98a0be,0x3278e964,0x9f1f9532,0xe0d392df,0xd3a0342b,0x8971f21e,
                    0x1b0a7441,0x4ba3348c,0xc5be7120,0xc37632d8,0xdf359f8d,0x9b992f2e,
                    0xe60b6f47,0x0fe3f11d,0xe54cda54,0x1edad891,0xce6279cf,0xcd3e7e6f,
                    0x1618b166,0xfd2c1d05,0x848fd2c5,0xf6fb2299,0xf523f357,0xa6327623,
                    0x93a83531,0x56cccd02,0xacf08162,0x5a75ebb5,0x6e163697,0x88d273cc,
                    0xde966292,0x81b949d0,0x4c50901b,0x71c65614,0xe6c6c7bd,0x327a140a,
                    0x45e1d006,0xc3f27b9a,0xc9aa53fd,0x62a80f00,0xbb25bfe2,0x35bdd2f6,
                    0x71126905,0xb2040222,0xb6cbcf7c,0xcd769c2b,0x53113ec0,0x1640e3d3,
                    0x38abbd60,0x2547adf0,0xba38209c,0xf746ce76,0x77afa1c5,0x20756060,
                    0x85cbfe4e,0x8ae88dd8,0x7aaaf9b0,0x4cf9aa7e,0x1948c25c,0x02fb8a8c,
                    0x01c36ae4,0xd6ebe1f9,0x90d4f869,0xa65cdea0,0x3f09252d,0xc208e69f,
                    0xb74e6132,0xce77e25b,0x578fdfe3,0x3ac372e6
            };
        }

        #endregion

        #region Conversions

        //gets the first byte in a uint
        private byte wordByte0(uint w)
        {
            return (byte)(w / 256 / 256 / 256 % 256);
        }

        //gets the second byte in a uint
        private byte wordByte1(uint w)
        {
            return (byte)(w / 256 / 256 % 256);
        }

        //gets the third byte in a uint
        private byte wordByte2(uint w)
        {
            return (byte)(w / 256 % 256);
        }

        //gets the fourth byte in a uint
        private byte wordByte3(uint w)
        {
            return (byte)(w % 256);
        }

        //converts a byte array to a hex string
        private string ByteToHex(byte[] bytes)
        {
            StringBuilder s = new StringBuilder();
            foreach (byte b in bytes)
                s.Append(b.ToString("x2"));
            return s.ToString();
        }

        //converts a hex string to a byte array
        private byte[] HexToByte(string hex)
        {
            byte[] r = new byte[hex.Length / 2];
            for (int i = 0; i < hex.Length - 1; i += 2)
            {
                byte a = GetHex(hex[i]);
                byte b = GetHex(hex[i + 1]);
                r[i / 2] = (byte)(a * 16 + b);
            }
            return r;
        }

        //converts a single hex character to it's decimal value
        private byte GetHex(char x)
        {
            if (x <= '9' && x >= '0')
            {
                return (byte)(x - '0');
            }
            else if (x <= 'z' && x >= 'a')
            {
                return (byte)(x - 'a' + 10);
            }
            else if (x <= 'Z' && x >= 'A')
            {
                return (byte)(x - 'A' + 10);
            }
            return 0;
        }

        #endregion
    }
}